Depends on your needs but anything below 8GB RAM nowadays is unusable for gaming really. 4GB VRAM is also cutting it close at 1080p.
If you can save up, wait a bit and grab Ryzen 2 3000 series in the summer, say August-September after the first issues are known with motherboards.
If your system is bloated then 8GB RAM will not cut it, plus some games do use 10GB+ even on a 16GB system, it's getting ridiculously out of hand with developers with how much some games use RAM and VRAM, it's OK if they use unused resources to speed up loading but when it's a hard requirement then that's way too much.
Doing a full upgrade is a better choice at this point than trying to get used parts especially if you're not at a place where such parts are common, plus many people already upgraded from those DDR3 systems. Although with a move to Ryzen 2 you may see some parts pop up on used market.
Decide your budget and needs. Do you want iGPU or dGPU, etc.
I don't think Ryzen 2 will have APUs at launch so you would need a dGPU. Those nice new APUs will probably arrive later. Considering how much improvement there is with Ryzen 2 I would not bother with Ryzen 1 or 1.5. Motherboard is also best bought with the new CPU and not buy the older while cheaper they will lack proper support for PCIe4, VRMs for the more cores CPUs, UEFI support until updates get done, etc.
Wait August, then buy new. Pretty much all at this point, there is likely nothing to reuse from old system except drives, fans, maybe case if you have a good one.
Last edited by JackCY; 06-13-2019 at 08:43 AM.